The use of lasers to alter the surface of objects is becoming more important as it becomes apparent that lasers may be precisely focused and the amount of energy transferred to the target can be closely controlled. Lasers have been used in eye surgery, for example, to treat the retina of diabetic persons. Lasers have also been used by doctors for other precise and delicate eye surgery.
In all of the prior art eye surgery procedures, as well as in other efforts to use laser beam pulses to act on or burn away tissue or other matter, a great concern arises about the ability to control the size and intensity of the beam. In addition, when multiple treatment pulses are intended, precise location of the beam is desirable.
Until recently, it has not been possible to provide a predetermined pattern of treatment where the intensity and duration of the laser pulse is controlled while simultaneously controlling the shape of the laser pulse and the location where the pulse strikes the target. It has been found that the cornea of the eye may be shaped or otherwise treated with a laser beam pulse in a plurality of locations on the eye to achieve a desired result. Until now, however, it has not been possible to automatically control the size and location of the beam. It has recently been discovered that predetermined control of the laser beam pulse may be accomplished by passing the laser beam through an iris that is centered on the axis of the laser beam. By controlling the size of the iris opening and simultaneously controlling the amount of laser energy passing through the iris aperture, the surface of the eye can be changed to correct for myopia or near sightedness. However, such a procedure has not found acceptance due to the limitations in beam sculpturing that an aperture of this type provides. In addition, the use of an iris only produces a round alteration in laser beam shape, and is therefor not useful for treatment of astigmatism, hyperopia, irregular shapes and even repair of over corrected or inaccurate corrections for myopia.
Accordingly, it is an object of the present invention to provide a system for sculpturing the shape of a laser beam to change the shape of the beam that impacts its intended target.
Another object of this invention is to provide a device which is useful in sculpturing laser beams into shapes that are not perfectly round.
Yet another object of the present invention is to provide a device capable of shaping a laser beam to permit treatment of astigmatism, hyperopia, irregular shapes and even repair of over corrected or inaccurate corrections for myopia.
Other objects will appear hereinafter.